Research On Coding Forward Scheme Of Streaming Data On Earth-moon Opportunity Networks

Along with the development of the trend of lunar exploration projects,the reserches of efficient communication technology between the earth and the moon has received increasing attention from all around the world.As a necessary guarantee for the future manned moon landing project,the timeliness and reliability of the communication system will have a great impact on scientifi c exploration projects.With the diversification of services,the type of communication services have changed from text to various large data services,and there is no direct reachable links between the source node and the destination.The traditional communication technology in point to point can't meet the needs of the future communication.Therefore,it is important to propose a communication scheme based on networks in the future lunar exploration field.Compared with the traditional Internet,the opportunistic network characteristics of the earth-moon communication network make the current transmission mechanism based on static topology unable to achieve good results.This paper is mainly aimed at the network transmission problem of the Earth-Moon communication in the future,aiming at reducing the delay of data transmission and network energy consumption,the streaming transmission model is established considering the constraints such as network dynamics in the Earth-Moon opportunity network.An adaptive transmission strategy based on rateless coding is proposed to solve the problem of efficient data communication under the Earth-Moon opportunity network.The research focuses specifically the following aspects:This paper studies the transmission mechanism problem under the Earth-Moon opportunity network.The data flow graph is used to analyze the storage and flow process of data in the system.The data flow and energy loss in the Earth-Moon opportunity network are analyzed based on the time slice static graph model.The rateless coding technology is introduced to match the link.The rateless coding technology is introduced to deal with the problem of long delay.Based on link conditions,the forwarding symbol is coded and designed,which is combined with the node single-hop selection scheme to constitute the coding forwarding scheme based on the streaming transmission model.By solving the optimization problem,the link stability function is designed to solve the optimal multi-hop link transmission path,so as to reduce the transmission delay and energy overhead of the high-capacity streaming service under the Earth-Moon opportunity networks.This paper also focuses on the further needs of the Earth-Moon opportunity networks,and studies the transmission strategies of different types of services.In this paper,delay sensitivity and reliability sensitivity are proposed.The mapping relationship between the sensitivity and link stability function(LSF)is given.It is used to study the transmission of different service types.At the same time,in terms of coding,the impact of service characteristics on the code length is analyzed.Based on the CFS-STM scheme,through the theoretical analysis of the impact mechanism of the service characteristics on the LSF and coding redundancy,a service-drive scheme,named with SDCFS-STM,is proposed to improve the service reception rate.Considering with energy consumption and delay,this scheme improves the transmission efficiency of the Earth-Moon opportunity network for different service types.